Assessing the impact of high-yielding varieties of maize in resettlement areas of Zimbabwe

"This study is part of a larger effort to explore the impact of agricultural research on poverty reduction. It examines the diffusion and impact of hybrid maize in selected resettlement areas of rural Zimbabwe, paying particular attention to varieties made widely available from the mid-1990s onwards. While "Zimbabwe's Green Revolution" of the early 1980s was characterized by the widespread adoption of hybrid maize varieties and significant increases in yields, the subsequent diffusion of newer varieties occurred more slowly and had a more modest impact. Several factors account for this. Government now plays a much-reduced role and one that increasingly focuses on "better farmers." Private-sector institutions that have entered the maize sector operate mainly in areas of high agricultural potential. Consequently, "adoption" partly reflects "choice" but also the (sometimes) limited physical availability of varieties. A further factor is the nature of the technology being introduced. Newer varieties are bred to meet the evolving needs of commercial farmers, but these new needs most notably improved disease resistance are not shared by the farmers in our survey and are not associated with significantly higher yields where use of fertilizers is limited. A further consideration is that information is disseminated via multiple channels and in a fragmentary fashion in an environment where tolerance of dissent is limited, the behavior of neighbors is viewed suspiciously and some actors involved in dissemination (such as extension workers) are increasingly viewed with mistrust. The presumption that farmers "learn from each other" is less applicable in circumstances such as these. Our case studies indicate links between the production of maize in excess of subsistence needs, the accumulation of assets such as livestock and tools, payment of school fees, and the acquisition of inputs such as fertilizer and labor for the subsequent cropping season. This coincides with the views of farmers who see high-yielding varieties of maize as an influential factor in raising livelihood above the level of poverty that prevailed when they first moved into the area. However, new varieties appear to have increased incomes only marginally. When we control for farmer characteristics and the endogeneity of adoption, use of these new varieties increases crop incomes only by about 10 percent; a 10-percent increase in maize income is associated with an increase in livestock holdings ranging from 4 to 12 percent. However, these modest impacts result in an improved ability to deal with vulnerability. Hybrids do raise productivity in maize production. Higher income from maize, and from other crops, leads to investment in livestock. And livestock holdings are an important means through which child health is protected when drought occurs. All such changes are associated with an improvement in well-being and a reduction in poverty. " Authors' AbstractPoverty alleviation ,Agricultural research ,Hybrid maize Zimbabwe ,Crop yields ,

Assessing the impact of high-yielding varieties of maize in resettlement areas of Zimbabwe

"This study is part of a larger effort to explore the impact of agricultural research on poverty reduction. It examines the diffusion and impact of hybrid maize in selected resettlement areas of rural Zimbabwe, paying particular attention to varieties made widely available from the mid-1990s onwards. While "Zimbabwe's Green Revolution" of the early 1980s was characterized by the widespread adoption of hybrid maize varieties and significant increases in yields, the subsequent diffusion of newer varieties occurred more slowly and had a more modest impact. Several factors account for this. Government now plays a much-reduced role and one that increasingly focuses on "better farmers." Private-sector institutions that have entered the maize sector operate mainly in areas of high agricultural potential. Consequently, "adoption" partly reflects "choice" but also the (sometimes) limited physical availability of varieties. A further factor is the nature of the technology being introduced. Newer varieties are bred to meet the evolving needs of commercial farmers, but these new needs most notably improved diseaseresistance are not shared by the farmers in our survey and are not associated with significantly higher yields where use of fertilizers is limited. A further consideration is that information is disseminated via multiple channels and in a fragmentary fashion in an environment where tolerance of dissent is limited, the behavior of neighbors is viewed suspiciously and some actors involved in dissemination (such as extension workers) are increasingly viewed with mistrust. The presumption that farmers "learn from each other" is less applicable in circumstances such as these. Our case studies indicate links between the production of maize in excess of subsistence needs, the accumulation of assets such as livestock and tools, payment of school fees, and the acquisition of inputs such as fertilizer and labor for the subsequent cropping season. This coincides with the views of farmers who see high-yielding varieties of maize as an influential factor in raising livelihood above the level of poverty that prevailed when they first moved into the area. However, new varieties appear to have increased incomes only marginally. When we control for farmer characteristics and the endogeneity of adoption, use of these new varieties increases crop incomes only by about 10 percent; a 10-percent increase in maize income is associated with an increase in livestock holdings ranging from 4 to 12 percent. However, these modest impacts result in an improved ability to deal with vulnerability. Hybrids do raise productivity in maize production. Higher income from maize, and from other crops, leads to investment in livestock. And livestock holdings are an important means through which child health is protected when drought occurs. All such changes are associated with an improvement in well-being and a reduction in poverty. " Authors' AbstractPoverty alleviation ,Agricultural research ,Hybrid maize Zimbabwe ,Crop yields ,livestock ,impact assessment ,

Children as Research Collaborators: Issues and Reflections from a Mobility Study in Sub-Saharan Africa

This paper reflects on issues raised by work with children in an ongoing child mobility study in three sub-Saharan African countries: Ghana, Malawi and South Africa. There are now 70 school pupils of varying ages involved in the project, but the paper is particularly concerned with the participation of those children 14 years and under. We examine the significant ethical issues associated with working with younger child researchers, and linked questions concerning the spaces open to them in African contexts where local cultural constructions of childhood and associated economic imperatives (which commonly drive family and household endeavour) help shape the attitudes of adults to children’s rights and responsibilities and inter-generational power relations

Dietary nitrate supplementation enhances high-intensity running performance in moderate normobaric hypoxia, independent of aerobic fitness.

Nitrate-rich beetroot juice (BRJ) increases plasma nitrite concentrations, lowers the oxygen cost (V̇O2) of steady-state exercise and improves exercise performance in sedentary and moderately-trained, but rarely in well-trained individuals exercising at sea-level. BRJ supplementation may be more effective in a hypoxic environment, where the reduction of nitrite into nitric oxide (NO) is potentiated, such that well-trained and less well-trained individuals may derive a similar ergogenic effect. We conducted a randomised, counterbalanced, double-blind placebo controlled trial to determine the effects of BRJ on treadmill running performance in moderate normobaric hypoxia (equivalent to 2500 m altitude) in participants with a range of aerobic fitness levels. Twelve healthy males (V̇O2max ranging from 47.1 to 76.8 ml kg(-1)·min(-1)) ingested 138 ml concentrated BRJ (∼15.2 mmol nitrate) or a nitrate-deplete placebo (PLA) (∼0.2 mmol nitrate). Three hours later, participants completed steady-state moderate intensity running, and a 1500 m time-trial (TT) in a normobaric hypoxic chamber (FIO2 ∼15%). Plasma nitrite concentrations were significantly greater following BRJ versus PLA 1 h post supplementation, and remained higher in BRJ throughout the testing session (p  0.05). These findings suggests that a high nitrate dose in the form of a BRJ supplement may improve running performance in individuals with a range of aerobic fitness levels conducting moderate and high-intensity exercise in a normobaric hypoxic environment

‘‘Beet-ing’’ the Mountain: A Review of the Physiological and Performance Effects of Dietary Nitrate Supplementation at Simulated and Terrestrial Altitude

Exposure to altitude results in multiple physiological consequences. These include, but are not limited to, a reduced maximal oxygen consumption, drop in arterial oxygen saturation, and increase in muscle metabolic perturbations at a fixed sub-maximal work rate. Exercise capacity during fixed work rate or incremental exercise and time-trial performance are also impaired at altitude relative to sea-level. Recently, dietary nitrate (NO3-) supplementation has attracted considerable interest as a nutritional aid during altitude exposure. In this review, we summarise and critically evaluate the physiological and performance effects of dietary NO3- supplementation during exposure to simulated and terrestrial altitude. Previous investigations at simulated altitude indicate that NO3- supplementation may reduce the oxygen cost of exercise, elevate arterial and tissue oxygen saturation, improve muscle metabolic function, and enhance exercise capacity/ performance. Conversely, current evidence suggests that NO3- supplementation does not augment the training response at simulated altitude. Few studies have evaluated the effects of NO3- at terrestrial altitude. Current evidence indicates potential improvements in endothelial function at terrestrial altitude following NO3- supplementation. No effects of NO3- supplementation have been observed on oxygen consumption or arterial oxygen saturation at terrestrial altitude, although further research is warranted. Limitations of the present body of literature are discussed, and directions for future research are provided

Effects of dietary nitrate supplementation on microvascular physiology at 4559 m altitude – a randomised controlled trial (Xtreme Alps)

Native highlanders (e.g. Sherpa) demonstrate remarkable hypoxic tolerance, possibly secondary to higher levels of circulating nitric oxide (NO) and increased microcirculatory blood flow. As part of the Xtreme Alps study (a randomised placebo-controlled trial of dietary nitrate supplementation under field conditions of hypobaric hypoxia), we investigated whether dietary supplementation with nitrate could improve NO availability and microvascular blood flow in lowlanders. Plasma measurements of nitrate, nitrite and nitroso species were performed together with measurements of sublingual (sidestream dark-field camera) and forearm blood flow (venous occlusion plethysmography) in 28 healthy adult volunteers resident at 4559 m for 1 week; half receiving a beetroot-based high-nitrate supplement and half receiving an identically-tasting low nitrate 'placebo'. Dietary supplementation increased plasma nitrate concentrations 4-fold compared to the placebo group, both at sea level (SL; 19.2 vs 76.9 μM) and at day 5 (D5) of high altitude (22.9 vs 84.3 μM,

Negotiating the Livelihoods of Children and Youth in Africa's Urban Spaces

This book deals with problems facing children and youth in African cities today. African populations have high growth rates and, consequently, relatively high proportions of young people

Assessing the impact of HYV maize in resettlement areas of Zimbabwe

High-yield varieties of maize have been widely adopted in Zimbabwe. Although germplasm from the Consultative Group on International Agricultural Research (CGIAR) system has been used in the development of hybrid maize varieties since Zimbabwe's independence, research and dissemination activities involved several organizations in both the public and private sectors. Further, even though adoption of earlier hybrids was widespread—in 1985, more than 85 percent of smallholder maize area was planted with hybrid maize and production doubled over the period 1979-85—rural poverty and child malnutrition remain endemic. Some observers argue that the gains from these hybrids have been concentrated in a few agroclimatic areas and that there has been little impact on child nutritional status. This argument has implications for policy debates not only about raising nutritional status within Zimbabwe but also for the CGIAR system, given its mandate to link improvements in agricultural technology to better nutrition.PRIFPRI2; GRP26; Country and regional food, nutrition, and agricultural strategies; Agriculture and Rural DevelopmentFCN

Assessing the impact of high-yielding varieties of maize in resettlement areas of Zimbabwe

This study is part of a larger effort to explore the impact of agricultural research on poverty reduction. It examines the diffusion and impact of hybrid maize in selected resettlement areas of rural Zimbabwe, paying particular attention to varieties made widely available from the mid-1990s onwards. While "Zimbabwe's Green Revolution" of the early 1980s was characterized by the widespread adoption of hybrid maize varieties and significant increases in yields, the subsequent diffusion of newer varieties occurred more slowly and had a more modest impact. Several factors account for this. Government now plays a much-reduced role and one that increasingly focuses on "better farmers." Private-sector institutions that have entered the maize sector operate mainly in areas of high agricultural potential. Consequently, "adoption" partly reflects "choice" but also the (sometimes) limited physical availability of varieties. A further factor is the nature of the technology being introduced. Newer varieties are bred to meet the evolving needs of commercial farmers, but these new needs -- most notably improved disease resistance -- are not shared by the farmers in our survey and are not associated with significantly higher yields where use of fertilizers is limited. A further consideration is that information is disseminated via multiple channels and in a fragmentary fashion in an environment where tolerance of dissent is limited, the behavior of neighbors is viewed suspiciously and some actors involved in dissemination (such as extension workers) are increasingly viewed with mistrust. The presumption that farmers "learn from each other" is less applicable in circumstances such as these. Our case studies indicate links between the production of maize in excess of subsistence needs, the accumulation of assets such as livestock and tools, payment of school fees, and the acquisition of inputs such as fertilizer and labor for the subsequent cropping season. This coincides with the views of farmers who see high-yielding varieties of maize as an influential factor in raising livelihood above the level of poverty that prevailed when they first moved into the area. However, new varieties appear to have increased incomes only marginally. When we control for farmer characteristics and the endogeneity of adoption, use of these new varieties increases crop incomes only by about 10 percent; a 10-percent increase in maize income is associated with an increase in livestock holdings ranging from 4 to 12 percent. However, these modest impacts result in an improved ability to deal with vulnerability. Hybrids do raise productivity in maize production. Higher income from maize, and from other crops, leads to investment in livestock. And livestock holdings are an important means through which child health is protected when drought occurs. All such changes are associated with an improvement in well-being and a reduction in poverty.Non-PRIFPRI1; GRP26FCN